Sunbird 94, brake pedal travels to floor

[badbrakes]

Sunbird 94, 215 000 kms. Runs like a charm except brakes. Intermittently, the brake pedal will travel to the floor... when that happens, I will approach a corner, press on the brakes and the pedal travels to the floor... the brakes do work (although the feeling is quite unnerving)... I then drive a little more and the brake pedal is 'back to normal' as if nothing happened !!! I checked the brake fluid (after the fact) and it is fine and topped up. As far as I can tell, no leaks in the system. In addition, I noticed that when it is very cold outside, (-20 celsius), the ABS light comes on... the brake still work well when the light is on but the ABS doesn't engage if I try stopping on slippery surface (wheels just lock up like non ABS car)... the pedal feels normal too. When weather gets warmer, ABS light goes off. I am assuming there is some kind of link between the ABS light on and the intermittent pedal travel but it hasn't been obvious to figure it out as both events don't necessarily occur at the same time.

Can anyone give me some hint as to what the 'heck' is going on with this car ? Altough it is a relatively old car, I have to keep it on the road... but don't want to break my neck (or anyone else's) driving it !

[GTP Dad]

It sounds like the ABS may be going bad. Although if it works when the weather is warm the problem may be with either the master cylinder or even the power brake booster. I would check the one way valve on the brake booster. It could be bad and costs only a couple of dollars to replace. If that does not fix the problem get a new vacuum booster and replace it. If still no success go to a wrecking yard or search for an ABS unit on the internet. Car-part.com can probably help you find one for a reasonable price. If there are no other problems with the car then it is worth fixing the one problem you have and it is a lot cheaper than a new car.